1. Field of the Invention
This invention relates generally to piezoelectric devices, and more particularly, to a piezoelectric device based on air-spaced composite cantilever beams for vibration energy harvesting.
2. Description of the Prior Art
Piezo devices that are known in the art are based on conventional solid cantilevers. Since of the distance between the active layer and neutral plane is small in such known devices, their sensitivity is limited. In addition, an unacceptably large percentage of the energy applied to the cantilever is wasted to bend the non-active layers, leading to a small signal-to-noise ratio.
There is, therefore, a need in the art for piezoelectric energy harvesting devices, and piezoresistive devices, that provide improved sensitivity.
There is additionally a need for piezo devices that generate increased voltage in response to vibrations, and afford correspondingly increased signal-to-noise ratio.